Although this wont help you out the rest of the time you may find this useful. I use blender for rendering things but this should still apply elsewhere. When rendering, use your gpu, not your cpu. Its quite a bit quicker. My I5 2500k (4.3ghz) can render the attached image in 01:11.62 (mins:secs.ms) My GTX560ti (1ghz core clock) can render the attached image in 00:11.78 (mins:secs.ms) This is with tile settings optimized to get the best out of both, so the CPU and GPU had performance settings set specifically for each. As i said above this should also help with rendering things other than images, such as video if your editor supports cuda/openGL. If you do use blender then i can link you to some useful things, but im not sure if it is relevant or not to you. And yes, the render is pretty low quality. I just wanted something that i could use to test this easily without taking years on the CPU side
If you want BeamNG specific results take a look at garyjpaterson's thread: http://www.beamng.com/threads/8595-BANANA-Benchmark-Results-Comparison or my price/performance spreadsheet (derived form his thread): https://docs.google.com/spreadsheets/d/1LpqZMpEgnsgFND3PMxTy2XEGko3ruMQ9JMxD9rDe2mo/pubhtml